Nagging Nausea

More than a nuisance on the long run

Illustration by Daniel Yagmin

All but the luckiest of runners have experienced the discomfort of nausea during a long run. It can easily ruin a training run, or, worse, a race you’ve trained months for. It can bring you to your knees, literally. What can you do about it? A whole lot.

Nausea while running is a multiple-threat danger. The key to defeating it is identifying which cause or causes are the day’s possible threats. Aside from sprinting some heinous hill, the most likely causes of running nausea are dehydration, salt intake, what you’re eating, heat and unsustainable running intensity.

1. Salt and Water“Hydration-and-electrolyte balance is number one,” says Meredith Terranova, sports nutritionist, ultrarunner and owner of Eating and Living Healthy, when asked what runners can do to prevent nausea. She continues, “A runner needs to balance the amount of water required for different conditions, then match that with a consistent intake of electrolytes, whether in drink or pill form.” Nausea resulting from dehydration and/or electrolyte imbalances occurs because both water and electrolytes are digestion requisites. Without the correct volumes of both, portions of the process break down and leftover stomach contents induce the desire to vomit.

2. Sweet But Not Too SweetThe proper water-electrolyte balance is hard to find, as consuming a too-high ratio of carbohydrates and water may make you ill, by slowing down gastric emptying (more on that later). Always take gels with at least six ounces of water, be careful not to “overdose” on carbs when combining gels and sports drink and never over-concentrate sports drink.

To be more technical, Robert Kunz, VP of Science and Technology at First Endurance, explains, “In cold conditions athletes can typically consume a much stronger concentration of calories to fluid, nearing 20 percent. In hot conditions when the body needs more fluid and where it is spending a fair amount of energy cooling itself, try not to exceed a concentration of eight percent, which equates to 100 calories per 12 ounces of fluid.”

Even if you’re maintaining the right carb-water balance, be careful not to consume too many calories in too short of a span. Terranova advises, “Remember, the body can only process a limited number of calories in an hour. So, ‘getting ahead’ or overeating in a short period of time causes most of the food to sit in your stomach.” As we now understand, lingering stomach contents often result in a nauseous feeling.

3. Blood FeudOur muscles are the big draw on our limited blood supply while running. However, during your long runs you’ll likely eat, as well as face an increased likelihood of prolonged heat exposure. As a result, you may be placing two or three extra demands on your blood supply.

Let’s look at the simple scenario of eating on the run. If you’re running at a relaxed effort, you’re not maxing out your body’s ability to supply oxygenated blood. Eat an energy gel, a Snickers or, say, a small slice of pizza and you (and your stomach) should feel fine.

Step up the pace, though, and the story changes. “The faster you run, the less blood flows to your gut,” explains Terranova. An increased effort draws additional blood flow to your hard-working muscles and away from your stomach. When that happens, your digestion slows and you’re left feeling less than rosy.

A hot day further complicates digestion. While the human body is well adapted to exercising in heat, dissipating heat through evaporational cooling provided by sweat on the skin, the process shunts blood to the skin.

It all adds up to three major draws on your blood flow: muscles, skin and stomach. Can you guess the loser? Yup, your stomach.

The simplest solution to any blood battle, advises Terranova, is simply backing off your effort for a while. Another short-term remedy is to eat just before a stretch in which you’ll be working less, such as a long downhill or an aid station you’ll be visiting for more than a couple minutes.